#!/usr/bin/env bash

hc() { "${herbstclient_command[@]:-herbstclient}" "$@" ;}
monitor=${1:-0}
geometry=( $(herbstclient monitor_rect "$monitor") )
if [ -z "$geometry" ] ;then
	echo "Invalid monitor $monitor"
	exit 1
fi
# geometry has the format W H X Y
x=${geometry[0]}
y=0
panel_width=${geometry[2]}
panel_height=13
font="-*-fixed-medium-*-*-*-10-*-*-*-*-*-*-*"
bgcolor="#202020"
selbg=$(hc get window_border_active_color)
selfg='#101010'

####
# Try to find textwidth binary.
# In e.g. Ubuntu, this is named dzen2-textwidth.
if which textwidth &> /dev/null ; then
	textwidth="textwidth";
elif which dzen2-textwidth &> /dev/null ; then
	textwidth="dzen2-textwidth";
else
	echo "This script requires the textwidth tool of the dzen2 project."
	exit 1
fi
####
# true if we are using the svn version of dzen2
# depending on version/distribution, this seems to have version strings like
# "dzen-" or "dzen-x.x.x-svn"
if dzen2 -v 2>&1 | head -n 1 | grep -q '^dzen-[^,]*-svn'; then
	dzen2_svn="true"
else
	dzen2_svn=""
fi

if awk -Wv 2>/dev/null | head -1 | grep -q '^mawk'; then
	# mawk needs "-W interactive" to line-buffer stdout correctly
	# http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=593504
	uniq_linebuffered() {
		awk -W interactive '$0 != l { print ; l=$0 ; fflush(); }' "$@"
	}
else
	# other awk versions (e.g. gawk) issue a warning with "-W interactive", so
	# we don't want to use it there.
	uniq_linebuffered() {
		awk '$0 != l { print ; l=$0 ; fflush(); }' "$@"
	}
fi

hc pad $monitor $panel_height

{
	### Event generator ###
	# based on different input data (mpc, date, hlwm hooks, ...) this generates events, formed like this:
	#   <eventname>\t<data> [...]
	# e.g.
	#   date    ^fg(#efefef)18:33^fg(#909090), 2013-10-^fg(#efefef)29

	mpc idleloop player &

	while true ; do
		# "date" output is checked once a second, but an event is only
		# generated if the output changed compared to the previous run.
		date +$'date\t^fg(#efefef)%H:%M^fg(#909090), %Y-%m-^fg(#efefef)%d'
		sleep 1 || break
	done > >(uniq_linebuffered) &
	childpid=$!
	hc --idle
	kill $childpid
} 2> /dev/null | {
	IFS=$'\t' read -ra tags <<< "$(hc tag_status $monitor)"
	visible=true
	date=""
	windowtitle=""
	while true ; do

		### Output ###
		# This part prints dzen data based on the _previous_ data handling run,
		# and then waits for the next event to happen.

		bordercolor="#26221C"
		separator="^bg()^fg($selbg)|"
		# draw tags
		for i in "${tags[@]}" ; do
			case ${i:0:1} in
				'#')
					echo -n "^bg($selbg)^fg($selfg)"
					;;
				'+')
					echo -n "^bg(#9CA668)^fg(#141414)"
					;;
				':')
					echo -n "^bg()^fg(#ffffff)"
					;;
				'!')
					echo -n "^bg(#FF0675)^fg(#141414)"
					;;
				*)
					echo -n "^bg()^fg(#ababab)"
					;;
			esac
			if [ ! -z "$dzen2_svn" ] ; then
				# clickable tags if using SVN dzen
				echo -n "^ca(1,\"${herbstclient_command[@]:-herbstclient}\" "
				echo -n "focus_monitor \"$monitor\" && "
				echo -n "\"${herbstclient_command[@]:-herbstclient}\" "
				echo -n "use \"${i:1}\") ${i:1} ^ca()"
			else
				# non-clickable tags if using older dzen
				echo -n " ${i:1} "
			fi
		done
		echo -n "$separator"
		echo -n "^bg()^fg() ${windowtitle//^/^^}"
		# small adjustments
		right="$song $separator^bg() $date $separator"
		right_text_only=$(echo -n "$right" | sed 's.\^[^(]*([^)]*)..g')
		# get width of right aligned text.. and add some space..
		width=$($textwidth "$font" "$right_text_only")
		echo -n "^pa($(($panel_width - $width)))$right"
		echo

		### Data handling ###
		# This part handles the events generated in the event loop, and sets
		# internal variables based on them. The event and its arguments are
		# read into the array cmd, then action is taken depending on the event
		# name.
		# "Special" events (quit_panel/togglehidepanel/reload) are also handled
		# here.

		# wait for next event
		IFS=$'\t' read -ra cmd || break
		# find out event origin
		case "${cmd[0]}" in
			tag*)
				#echo "resetting tags" >&2
				IFS=$'\t' read -ra tags <<< "$(hc tag_status $monitor)"
				;;
			date)
				#echo "resetting date" >&2
				date="${cmd[@]:1}"
				;;
			quit_panel)
				exit
				;;
			togglehidepanel)
				currentmonidx=$(hc list_monitors | sed -n '/\[FOCUS\]$/s/:.*//p')
				if [ "${cmd[1]}" -ne "$monitor" ] ; then
					continue
				fi
				if [ "${cmd[1]}" = "current" ] && [ "$currentmonidx" -ne "$monitor" ] ; then
					continue
				fi
				echo "^togglehide()"
				if $visible ; then
					visible=false
					hc pad $monitor 0
				else
					visible=true
					hc pad $monitor $panel_height
				fi
				;;
			reload)
				exit
				;;
			focus_changed|window_title_changed)
				windowtitle="${cmd[@]:2}"
				;;
			player)
				song=$(mpc current -f '%artist% - %title%')
				;;
		esac
	done

	### dzen2 ###
	# After the data is gathered and processed, the output of the previous block
	# gets piped to dzen2.

} 2> /dev/null | dzen2 -w $panel_width -x $x -y $y -fn "$font" -h $panel_height \
	-e 'button3=;button4=exec:herbstclient use_index -1;button5=exec:herbstclient use_index +1' \
	-ta l -bg "$bgcolor" -fg '#efefef'
